• Korean Journal of Clinical Laboratory Science
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• v.55 no.3
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• pp.219-226
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• 2023

Transcranial doppler ultrasonography (TCD) applies a low frequency of 2 MHz to measure the blood flow velocity and waveform within the skull. Medical technologists at several hospitals are conducting these examinations, and education is being imparted in many schools and academic societies. However, the skill of the tester is of utmost importance when performing TCD. Technicians who are conducting the procedure for the first time have trouble locating the blood vessels, and some experienced personnel are worried because too many blood vessels are present. Since this procedure does not directly look at and measure blood vessels, there are several limitations and difficulties. Therefore, this study aims to provide some help by introducing precautions and suggestions for TCD technicians conducting the test.

• Korean Journal of Radiology
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• v.21 no.7
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• pp.900-907
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• 2020

Objective: To investigate the predictive value of intraplaque neovascularization (IPN) for cardiovascular outcomes. Materials and Methods: We evaluated 217 patients with coronary artery disease (CAD) (158 men; mean age, 68 ± 10 years) with a maximal carotid plaque thickness ≥ 1.5 mm for the presence of IPN using contrast-enhanced ultrasonography. We compared patients with (n = 116) and without (n = 101) IPN during the follow-up period and investigated the predictors of major adverse cardiovascular events (MACE), including cardiac death, myocardial infarction, coronary artery revascularization, and transient ischemic accident/stroke. Results: During the mean follow-up period of 995 ± 610 days, the MACE rate was 6% (13/217). Patients with IPN had a higher maximal thickness than those without IPN (2.86 ± 1.01 vs. 2.61 ± 0.84 mm, p = 0.046). Common carotid artery-peak systolic velocity, left ventricular mass index (LVMI), and ventricular-vascular coupling index were significantly correlated with MACE. However, on multivariate Cox regression analysis, increased LVMI was independently related to MACE (p < 0.05). The presence of IPN could not predict MACE. Conclusion: The presence of IPN was related to a higher plaque thickness but could not predict cardiovascular outcomes better than conventional clinical factors in patients with CAD.

• Childhood Kidney Diseases
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• v.28 no.2
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• pp.74-79
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• 2024

Purpose: To compare the Doppler sonographic findings of the left renal vein (LRV) of children diagnosed with nutcracker syndrome with and without orthostatic proteinuria. Methods: Fifty and 53 consecutive children with and without orthostatic proteinuria, respectively, underwent renal Doppler ultrasonography examinations. The peak velocity (PV) was measured at the hilar portion of the LRV and between the aorta and superior mesenteric artery. Renal Doppler ultrasonography findings and clinical data including urine protein-to-creatinine ratio (UPCR) were compared according to the presence or absence of orthostatic proteinuria. Results: Between the two groups, no significant differences were observed in terms of age or sex. The PV ratio between the aortomesenteric and hilar portions was 7.79±2.65 and 6.32±3.01 in children with and without orthostatic proteinuria, respectively (P=0.009). No significant differences were observed between the two groups in terms of the UPCR in the first morning urine sample. However, the UPCR in the afternoon urine sample was significantly higher in children with orthostatic proteinuria than in those without orthostatic proteinuria (0.49±0.46 mg/mg vs. 0.11±0.04 mg/mg, P<0.001). Furthermore, the PV ratio between the aortomesenteric and hilar portions revealed a positive correlation with the ratio of UPCR of the afternoon to that of first morning urine samples (R=0.21, P=0.034). Conclusions: This study suggests that there can be a significant correlation of the PV ratio between the aortomesenteric and hilar portion of the LRV with orthostatic proteinuria in pediatric patients with nutcracker syndrome.

• Earthquakes and Structures
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• v.27 no.2
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• pp.127-142
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• 2024

The amount of wave propagation through a rubber concrete construction is the subject of the current investigation. Rubber tire waste was used to make two different types of cement mixtures. One type contains sand substitute in amounts ranging from 15% to 60% of the total volume, while the other has gravel with diameters of 3/8 and 8/15 and 15% sand in the same mixture. A wide variety of concrete forms and compositions were created, and their viscous and solid state characteristics were assessed, along with their short-, medium-, and long-term strengths. Diffusion, density, mechanical strength resistance to compressive force, and ultrasound wave propagation were also assessed. The water-to-cement ratio and plasticizer were used in this investigation. In the second part of the study, an analytical model is presented that simulates the experimental model in predicting the speed of waves and the frequencies accompanying them for this type of mixture. Higher order shear deformation beam theory for wave propagation in the rubberized concrete beam is developed, considering the bidirectional distribution, which is primarily expressed by the density, the Poisson coefficient, and Young's modulus. Hamilton's concept is used to determine the governing equations of the wave propagation in the rubberized concrete beam structure. When the analytical and experimental results for rubber concrete beams were compared, the outcomes were very comparable. The addition of rubber gravel and sandy rubber to the mixture both resulted in a discernible drop in velocities and frequencies, according to the data.

• The Journal of Internal Korean Medicine
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• v.28 no.2
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• pp.250-261
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• 2007

Objectives : The purpose of this study was to evaluate the blood flow using doppler ultrasound of the MCA, ACA, PCA, BA, ICA in the patients with risk factor for stroke. Methods : 110 patients with risk factor for stroke were selected who had hypertension, diabetes mellitus, hyperlipidemia, or heart disease, as well as 89 healthy adults who did not have any symptoms of those diseases. To evaluate the blood flow, the Vs and Vm of the MCA, ACA, PCA, BA, and ICA in the two groups were measured. Result : In normal healthy adults, subjects showed a decrease in the Vs and Vm: with advancing in age, there was a significant difference in the Vs of MCA, PCA, BA, and ICA. There was a significant difference in the Vm of MCA, PCA, BA, and ICA. In normal healthy adults, females showed high velocities in all examined vessels. There was a significant difference in the Vs of BA. There was a significant difference in the Vm of BA, and ICA. There was a decrease in the Vs, and Vm of all examined vessels of patients with risk factors for stroke in comparison with normal healthy adults. There was no significant difference in the Vs. There was a significant difference in the Vm of MCA, ACA, and PCA. Results were the same between patients aged under 50 and total patients in the Vs and Vm of examined vessels. There were differences between patients aged over 50 and total patients in the Vs of MCA, PCA, BA and for patients aged over 50; patients with risk factor for stroke who had hypertension, diabetes mellitus, hyperlipidemia, or heat disease has higher Vs than healthy adults. Conclusions : There was a significant difference in the blood flow velocity between patients with risk factors for stroke and healthy adults. However, this result was different from results of comparison of TCD findings between patients and healthy individuals by age. Therefore, more detailed studies about aged patients are needed.

• The Journal of Korean Medicine
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• v.26 no.1 s.61
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• pp.115-122
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• 2005

Background and objective: Gastrodiae Rhizoma (GR), the rhizoma of Gastrodia elata BL., is one of the popular drugs to treat headache, dizziness, blackout, numbness of limbs, hemiplegia, facial paralysis, dysphrasia, and infantile convulsions. It has been reported that it provides an antihypertensive effect and lowers cerebrovascular resistance in animal experiments. However, there has been no data about these effects with human subjects. In this study, the author examined the effect of Gastrodiae water extracts on blood pressure and cerebrovascular reactivity in human subjects. Methods: We selected 16 normal volunteers, who were divided into 2 groups: Gastrodiae extract administration group and placebo (creamy powder) group. Using transcranial Doppler ultrasound, we monitored changes of mean flow velocity and breath-holding induced CO2 reactivity of middle cerebral artery in both groups. Mean blood pressure, heart rate and PETCO2 were measured using Compact Anesthesia Monitor. In both groups, all evaluation was performed during basal condition, and repeated at 30, 60, and 90 min after administration. Results: Gastrodiae extract decreased CO2 reactivity after administration, reaching the lowest level at 90 minutes $(-29.1\%\;vs.\;basal\;level)$, which showed significant difference compared with the placebo group (p = 0.004). In the placebo group, the pulse rates tended to decrease over time (at 90 minute, $-5.2\%$ vs. basal level) while in the Gastrodiae group the values showed nearly no change, which showed significant difference between both groups (p = 0.036). However, the changes of mean blood pressure and mean flow velocity did not show significant difference between both groups. Conclusion : This study demonstrated that Gastrodiae extract significantly decreased breath-holding induced CO2 reactivity. This result suggests that the clinical effect of Gastrodiae extract might be caused by increasing cerebral blood flow via dilation of cerebral resistant vessels instead of antihypertensive effect.

• The Journal of Korean Medicine
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• v.27 no.3 s.67
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• pp.38-50
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• 2006

Objectives: The aim of this study was to evaluate the effects of Korean ginseng (KG), Korean red ginseng (KRG) and fermented Korean red ginseng (FKRG) extracts on cerebral hemodynamics and to compare distinction of each extract. Methods: Ten healthy male volunteers $(26.0{\pm}1.8yrs)$ participated in the study according to double-blind and cross-over protocols. Each volunteer was blindly administered 500mg of KG, KRG, FKRG extract or placebo (Dextrin). Blinded researchers measured changes of hyperventilation-induced cerebrovascular reactivity (CVR), mean blood flow velocity (MBFV) of middle cerebral arteries (MCAs) and corrected blood flow velocity at $P_{ETCO2}=40mmHg$ (CV40) using transcranial Doppler ultrasound (DWL Co., Germany). Researchers also observed changes of mean blood pressure (MBP), pulse rate (PR) and expiratory $CO_2$ using S/5 Collector (Datex-Ohmeda Co., Finland). The evaluation was performed at basal condition, and repeated at 1, 2, 3, 4 and 5 hours after administration. Results: MBFV and CV40 in the KRG group tended to rise at I hour after administration, while those of the FKRG group tended to rise at 2 hours after administration. CVR increased significantly after 1 hour in the KRG group (p=0.009) and after 2 hours in the FKRG group (p=0.035), respectively. The KG group showed increasing tendency at 4 hours after administration. No group showed significant difference from the placebo in changes of MBP and PR. Conclusions: It is suggested that KG, KRG and FKRG extracts have effects of enhancing CVR and thus of increasing cerebral blood flow in human subjects.

• Journal of Biomedical Engineering Research
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• v.23 no.1
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• pp.49-60
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• 2002

Receive dynamic focusing with an array transducer can provide near optimum resolution only in the vicinity of transmit focal depth. A customary method to increase the depth of field is to combine several beams with different focal depths, with an accompanying decrease in the frame rate. In this Paper. we Present a simultaneous multiple transmit focusing method in which chirp signals focused at different depths are transmitted at the same time. These chirp signals are mutually orthogonal in a sense that the autocorrelation function of each signal has a narrow mainlobe width and low sidelobe levels. and the crossorelation function of any Pair of the signals has values smaller than the sidelobe levels of each autocorrelation function. This means that each chirp signal can be separated from the combined received signals and compressed into a short pulse. which is then individually focused on a separate receive beamformer. Next. the individually focused beams are combined to form a frame of image. Theoretically, any two chirp signals defined over two nonoverlapped frequency bands are mutually orthogonal In the present work. however, a tractional overlap of adjacent frequency bands is permitted to design more chirp signals within a given transducer bandwidth. The elevation of the rosscorrelation values due to the frequency overlap could be reduced by alternating the direction of frequency sweep of the adjacent chirp signals We also observe that the Proposed method provides better images when the low frequency chirp is focused at a near Point and the high frequency chirp at a far point along the depth. better lateral resolution is obtained at the far field with reasonable SNR due to the SNR gain in Pulse compression Imaging .

• Biomedical Science Letters
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• v.12 no.4
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• pp.375-383
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• 2006

The physiological responses following stress are different in individual or personality. We performed this study to clarify gender differences in influences of noise stress on physiological factors. 70 healthy subjects, which was divided man (n=30) and woman (n=40) groups, were exposed to 85 decibels of excavator noise for 15 minutes. Cardiac factors such as heart rate (HR), systolic and diastolic blood pressures (SBP and DBP, respectively), and heart rate-systolic pressure product (RPP) were determined. Transcranial Doppler ultrasound (TCD) was used to measure mean blood flow velocity (Vm), pulsatility index (PI), and resistance index (RI) in the middle, anterior and posterior cerebral arteries (MCA, ACA and PCA, respectively) before and during noise exposure. Cortisol level and hematological variables were also measured before (baseline) and immediately after the end of noise exposure. In the both groups HR, SBP, and RPP significantly decreased during noise exposure (P<0.05) but not significantly different between two groups (P>0.05). Vms of three cerebral arteries in man group decreased, whereas Vm of PCA in woman group fell during noise exposure (P<0.05). Vm, PI and RI in MCA and ACA during noise exposure were low in man group compared with woman group (P<0.05). Vm of PCA was low, whereas PI and RI of PCA were high in man group compared with woman group during noise exposure (P<0.05). Total leukocyte and red blood cell (RBC) counts slightly decreased during noise exposure but not significant (P>0.05). Levels in hematological variables decreased but not significant changed following noise exposure. Decreased rate of total leukocyte in man group was higher (P<0.05). Cortisol levels in the both groups decreased immediately after the end of noise exposure, while the decreased rate in man group was greater than that in woman group (p<0.05). These findings indicate that a transient exposure to experimental excavator noise may cause decreased changes in cardiac factors, cerebral hemodynamics and cortisol levels and the changes may be greater in men than in women.

• Journal of the Korean Institute of Gas
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• v.20 no.6
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• pp.50-57
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• 2016

Pipeline is one of the most abundant components in petrochemical plant. It plays a critical role in transporting fluids. Some pipelines are thermally insulated by wrapping them with insulating materials to prevent the loss of energy. However, when corrosion begins under insulation, it cannot be easily seen without unwrapping the cover, and thus corrossion should be detected using a non-destructive ways such as ultrasound guided wave. In this paper, the piping where the CUI (Corrosion Under Insulation) which occurs in the insulation parts guided waves effectively the optimum condition which is theoretical for selected guided waves phase velocity dispersion curve and wave-structure. The results of this study are expected to be directly utilized for onsite inspection of pipeline's CUI in many petrochemical plants.